mkeficapsule: Add support for embedding public key in a dtb

Add options for embedding the public key esl(efi signature list) file
to the platform's dtb. The esl file is then retrieved and used for
authenticating the capsule to be used for updating firmare components
on the platform.

The esl file can now be embedded in the dtb by invoking the following
command
mkeficapsule -K <pub_key.esl> -D <dtb>

In the scenario where the esl file is to be embedded in an overlay,
this can be done through the following command
mkeficapsule -O -K <pub_key.esl> -D <dtb>

This will create a node named 'signature' in the dtb, and the esl file
will be stored as 'capsule-key'

Signed-off-by: Sughosh Ganu <sughosh.ganu@linaro.org>

tools/Makefile

@@ -218,6 +218,7 @@ hostprogs-$(CONFIG_MIPS) += mips-relocs
 hostprogs-$(CONFIG_ASN1_COMPILER)	+= asn1_compiler
 HOSTCFLAGS_asn1_compiler.o = -idirafter $(srctree)/include
 
+mkeficapsule-objs	:= mkeficapsule.o $(LIBFDT_OBJS)
 hostprogs-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += mkeficapsule
 
 # We build some files with extra pedantic flags to try to minimize things

tools/mkeficapsule.c

@@ -4,16 +4,22 @@
  *		Author: AKASHI Takahiro
  */
 
+#include <errno.h>
 #include <getopt.h>
 #include <malloc.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include <linux/types.h>
+
+#include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include "fdt_host.h"
+
 typedef __u8 u8;
 typedef __u16 u16;
 typedef __u32 u32;
@@ -23,6 +29,9 @@ typedef __s32 s32;
 
 #define aligned_u64 __aligned_u64
 
+#define SIGNATURE_NODENAME	"signature"
+#define OVERLAY_NODENAME	"__overlay__"
+
 #ifndef __packed
 #define __packed __attribute__((packed))
 #endif
@@ -43,6 +52,9 @@ static struct option options[] = {
 	{"raw", required_argument, NULL, 'r'},
 	{"index", required_argument, NULL, 'i'},
 	{"instance", required_argument, NULL, 'I'},
+	{"dtb", required_argument, NULL, 'D'},
+	{"public key", required_argument, NULL, 'K'},
+	{"overlay", no_argument, NULL, 'O'},
 	{"help", no_argument, NULL, 'h'},
 	{NULL, 0, NULL, 0},
 };
@@ -51,14 +63,183 @@ static void print_usage(void)
 {
 	printf("Usage: %s [options] <output file>\n"
 	       "Options:\n"
-	       "\t--fit <fit image>      new FIT image file\n"
+
-	       "\t--raw <raw image>      new raw image file\n"
+	       "\t--fit <fit image>       new FIT image file\n"
-	       "\t--index <index>        update image index\n"
+	       "\t--raw <raw image>       new raw image file\n"
-	       "\t--instance <instance>  update hardware instance\n"
+	       "\t--index <index>         update image index\n"
-	       "\t--help                 print a help message\n",
+	       "\t--instance <instance>   update hardware instance\n"
+	       "\t--public-key <key file> public key esl file\n"
+	       "\t--dtb <dtb file>        dtb file\n"
+	       "\t--overlay               the dtb file is an overlay\n"
+	       "\t--help                  print a help message\n",
 	       tool_name);
 }
 
+static int fdt_add_pub_key_data(void *sptr, void *dptr, size_t key_size,
+				bool overlay)
+{
+	int parent;
+	int ov_node;
+	int frag_node;
+	int ret = 0;
+
+	if (overlay) {
+		/*
+		 * The signature would be stored in the
+		 * first fragment node of the overlay
+		 */
+		frag_node = fdt_first_subnode(dptr, 0);
+		if (frag_node == -FDT_ERR_NOTFOUND) {
+			fprintf(stderr,
+				"Couldn't find the fragment node: %s\n",
+				fdt_strerror(frag_node));
+			goto done;
+		}
+
+		ov_node = fdt_subnode_offset(dptr, frag_node, OVERLAY_NODENAME);
+		if (ov_node == -FDT_ERR_NOTFOUND) {
+			fprintf(stderr,
+				"Couldn't find the __overlay__ node: %s\n",
+				fdt_strerror(ov_node));
+			goto done;
+		}
+	} else {
+		ov_node = 0;
+	}
+
+	parent = fdt_subnode_offset(dptr, ov_node, SIGNATURE_NODENAME);
+	if (parent == -FDT_ERR_NOTFOUND) {
+		parent = fdt_add_subnode(dptr, ov_node, SIGNATURE_NODENAME);
+		if (parent < 0) {
+			ret = parent;
+			if (ret != -FDT_ERR_NOSPACE) {
+				fprintf(stderr,
+					"Couldn't create signature node: %s\n",
+					fdt_strerror(parent));
+			}
+		}
+	}
+	if (ret)
+		goto done;
+
+	/* Write the key to the FDT node */
+	ret = fdt_setprop(dptr, parent, "capsule-key",
+			  sptr, key_size);
+
+done:
+	if (ret)
+		ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
+
+	return ret;
+}
+
+static int add_public_key(const char *pkey_file, const char *dtb_file,
+			  bool overlay)
+{
+	int ret;
+	int srcfd = 0;
+	int destfd = 0;
+	void *sptr = NULL;
+	void *dptr = NULL;
+	off_t src_size;
+	struct stat pub_key;
+	struct stat dtb;
+
+	/* Find out the size of the public key */
+	srcfd = open(pkey_file, O_RDONLY);
+	if (srcfd == -1) {
+		fprintf(stderr, "%s: Can't open %s: %s\n",
+			__func__, pkey_file, strerror(errno));
+		goto err;
+	}
+
+	ret = fstat(srcfd, &pub_key);
+	if (ret == -1) {
+		fprintf(stderr, "%s: Can't stat %s: %s\n",
+			__func__, pkey_file, strerror(errno));
+		goto err;
+	}
+
+	src_size = pub_key.st_size;
+
+	/* mmap the public key esl file */
+	sptr = mmap(0, src_size, PROT_READ, MAP_SHARED, srcfd, 0);
+	if ((sptr == MAP_FAILED) || (errno != 0)) {
+		fprintf(stderr, "%s: Failed to mmap %s:%s\n",
+			__func__, pkey_file, strerror(errno));
+		goto err;
+	}
+
+	/* Open the dest FDT */
+	destfd = open(dtb_file, O_RDWR);
+	if (destfd == -1) {
+		fprintf(stderr, "%s: Can't open %s: %s\n",
+			__func__, dtb_file, strerror(errno));
+		goto err;
+	}
+
+	ret = fstat(destfd, &dtb);
+	if (ret == -1) {
+		fprintf(stderr, "%s: Can't stat %s: %s\n",
+			__func__, dtb_file, strerror(errno));
+		goto err;
+	}
+
+	dtb.st_size += src_size + 0x30;
+	if (ftruncate(destfd, dtb.st_size)) {
+		fprintf(stderr, "%s: Can't expand %s: %s\n",
+			__func__, dtb_file, strerror(errno));
+		goto err;;
+	}
+
+	errno = 0;
+	/* mmap the dtb file */
+	dptr = mmap(0, dtb.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
+		    destfd, 0);
+	if ((dptr == MAP_FAILED) || (errno != 0)) {
+		fprintf(stderr, "%s: Failed to mmap %s:%s\n",
+			__func__, dtb_file, strerror(errno));
+		goto err;
+	}
+
+	if (fdt_check_header(dptr)) {
+		fprintf(stderr, "%s: Invalid FDT header\n", __func__);
+		goto err;
+	}
+
+	ret = fdt_open_into(dptr, dptr, dtb.st_size);
+	if (ret) {
+		fprintf(stderr, "%s: Cannot expand FDT: %s\n",
+			__func__, fdt_strerror(ret));
+		goto err;
+	}
+
+	/* Copy the esl file to the expanded FDT */
+	ret = fdt_add_pub_key_data(sptr, dptr, src_size, overlay);
+	if (ret < 0) {
+		fprintf(stderr, "%s: Unable to add public key to the FDT\n",
+			__func__);
+		goto err;
+	}
+
+	return 0;
+
+err:
+	if (sptr)
+		munmap(sptr, src_size);
+
+	if (dptr)
+		munmap(dptr, dtb.st_size);
+
+	if (srcfd >= 0)
+		close(srcfd);
+
+	if (destfd >= 0)
+		close(destfd);
+
+	return -1;
+}
+
 static int create_fwbin(char *path, char *bin, efi_guid_t *guid,
 			unsigned long index, unsigned long instance)
 {
@@ -173,16 +354,22 @@ err_1:
 int main(int argc, char **argv)
 {
 	char *file;
+	char *pkey_file;
+	char *dtb_file;
 	efi_guid_t *guid;
 	unsigned long index, instance;
 	int c, idx;
+	int ret;
+	bool overlay = false;
 
 	file = NULL;
+	pkey_file = NULL;
+	dtb_file = NULL;
 	guid = NULL;
 	index = 0;
 	instance = 0;
 	for (;;) {
-		c = getopt_long(argc, argv, "f:r:i:I:v:h", options, &idx);
+		c = getopt_long(argc, argv, "f:r:i:I:v:D:K:Oh", options, &idx);
 		if (c == -1)
 			break;
 
@@ -209,22 +396,44 @@ int main(int argc, char **argv)
 		case 'I':
 			instance = strtoul(optarg, NULL, 0);
 			break;
+		case 'K':
+			if (pkey_file) {
+				printf("Public Key already specified\n");
+				return -1;
+			}
+			pkey_file = optarg;
+			break;
+		case 'D':
+			if (dtb_file) {
+				printf("DTB file already specified\n");
+				return -1;
+			}
+			dtb_file = optarg;
+			break;
+		case 'O':
+			overlay = true;
+			break;
 		case 'h':
 			print_usage();
 			return 0;
 		}
 	}
 
-	/* need a output file */
+	/* need a fit image file or raw image file */
-	if (argc != optind + 1) {
+	if (!file && !pkey_file && !dtb_file) {
+		printf("%s: %d\n", __func__, __LINE__);
 		print_usage();
 		return -1;
 	}
 
-	/* need a fit image file or raw image file */
+	if (pkey_file && dtb_file) {
-	if (!file) {
+		ret = add_public_key(pkey_file, dtb_file, overlay);
-		print_usage();
+		if (ret == -1) {
-		return -1;
+			printf("Adding public key to the dtb failed\n");
+			return -1;
+		} else {
+			return 0;
+		}
 	}
 
 	if (create_fwbin(argv[optind], file, guid, index, instance)